Continental Drift and Seafloor Spreading Quiz

The alternating magnetic stripes on the ocean floor are best explained by:

• Shifts in the direction of tectonic plate movement over time

• Differences in mineral composition caused by varying magma sources

• Seasonal changes in ocean current patterns affecting sediment deposits

• Reversals in Earth’s magnetic field recorded in cooling basaltic rocks

Fossils of the reptile Mesosaurus are found in both South America and Africa. Which conclusion is most consistent with Continental Drift Theory?

• The continents were once joined before moving apart

• The reptile developed the ability to cross large oceans

• The continents have always been in their current locations

• Ocean currents transported the reptile’s remains across seas

Which observation supports the idea of seafloor spreading?

• Rocks near the mid-ocean ridge are younger than those farther away

• Sediment thickness increases with distance from the mid-ocean ridge

• Magnetic minerals align with Earth’s magnetic poles in alternating patterns

• Fossils of marine organisms become older away from the spreading center

What is the main source of new oceanic crust in seafloor spreading?

• Cooling of water in deep ocean trenches

• Sediment deposition from rivers into the ocean

• Weathering of rocks along continental shorelines

• Magma rising from the mantle at mid-ocean ridges

If seafloor spreading continues, what will likely happen to the distance between South America and Africa?

• It will fluctuate as continents rotate in place

• It will increase gradually over millions of years

• It will decrease as oceanic plates move together

• It will remain constant due to stable plate positions

What evidences do scientists use to support the Continental Drift Theory?

• rocks, fossils, air

• rocks, water, ice

• rocks, fossils, climate

• rocks, fossils, human beings

Which discovery in the 20th century convinced scientists to accept continental drift?

• Fossil remains of the same species on continents far apart

• Similar rock structures found on different continents

• Symmetrical magnetic patterns on either side of mid-ocean ridges

• Matching glacial deposits on continents separated by oceans

Wegener suggested that coal beds discovered in Antarctica indicated that this continent was:

• once underwater.

• once near the equator.

• always frozen.

• part of Africa

Sediment thickness increases as you move away from a mid-ocean ridge. Which process explains this?

• Sediment is deposited only near continents

• Older crust collects more sediment over time

• Mid-ocean ridges trap sediments as they form

• Ocean currents remove sediment from the ridge

Which scenario best demonstrates evidence for past continental connections?

• Coral reefs forming in the same latitudes across different oceans

• Ancient sand dunes preserved in both Europe and Asia

• Fossil remains of the same reptile species in Africa and South America

• Identical volcanic rock layers in Hawaii and Iceland